The disclosure relates to a roller bearing and to an axial piston machine of swashplate design with such a roller bearing.
In the case of axial piston machines, the working volume of which is adjustable, it is known to design a swashplate as a swivel cradle which can be swiveled towards a housing via an adjustment device. By adjusting the swivel angle of the swivel cradle in relation to a cylinder drum revolving about an axis, the stroke of the pistons coupled to the swashplate is adjusted during their revolution about an axis of the axial piston machines.
Since, during the adjustment of the swivel angle, the swivel cradle is moved relative to the housing of the axial piston machine, bearings are known for the mounting of the swivel cradle on both sides of the axis, said bearings being designed as pairs of circular-arc-shaped tracks, of which one track having a larger diameter is arranged on the housing, while a track having a smaller diameter is arranged on the swivel cradle.
During the operation of axial piston machines of this type, a respective supporting force is produced by the pistons against the swashplate, depending on the working pressure acting on the pistons, which supporting force can lead to deflection in the region of the swashplate approximately along the axis between the two bearings. Between the circular-arc-shaped tracks of each bearing, this results in a disadvantageous change in the positions of the tracks with respect to one another since the swivel-cradle track tilts in relation to the housing track and comes into an oblique position.
In documents DE 197 27 071 A1 and DE 10 2008 013 010 A1, the two tracks of each bearing form a plain bearing. DE 197 27 071 A1 discloses a hydrostatic load alleviation in the two plain bearings, said load alleviation being optimized in respect of the deflection of the swivel cradle. DE 10 2008 013 010 A1 has flexible regions in order to compensate for the deflection of the swivel cradle. It is proposed to flexibly configure that region of the housing against which a resting bearing shell bears, or that region of the swivel cradle that bears against the bearing shell and that moves in a sliding manner in relation to the bearing shell. Alternatively, it is proposed to configure the bearing shell itself to be flexible.
Document DE 10 2012 214 343 A1 presents a mounting of a swivel cradle of an axial piston machine, wherein each of the two bearings has a pair of circular-arc-shaped raceways, between which rolling elements are clamped. The swivel cradle is therefore supported in the housing via two roller bearings. The rolling elements are of barrel-shaped design, and therefore a deflection of the swivel cradle, and therefore a tilting or oblique position of the swivel-cradle raceway, can be compensated for by the shape of the rolling element by the contact points of the swivel cradle raceway against the rolling elements changing.
A disadvantage of such axial piston machines is that the barrel-shaped rolling elements always only have a reduced contact width, i.e. a reduced linear contact. During the operation of the axial piston machine with the deflection, which has to be tolerated, of the swashplate, the swivel cradle contact regions and also the housing contact regions migrate in the direction of the inner edge of the rolling elements. The bearing properties of the rolling elements are therefore disadvantageously affected.